Evidence demonstrates that ambulatory care is unsafe, and more unsafe with elderly patients. But little is known about what underlies the safety problems. That led AHRQ to launch the Ambulatory Care Patient Safety Proactive Risk Assessment FOA, under which we were awarded a grant to identify hazards in the primary care of the elderly. We have enrolled all 15 clinics (eight urban, seven rural, nine using electronic health records [EHRs] and six not using EHRs), and proactive hazard analysis of the data show that underlying nearly all of the hazards is one most serious hazard: physicians are experiencing information chaos. Information chaos is simultaneous (a) information overload, (b) information underload, (c) uncertainty about information, and (d) lack of awareness of some information. In human factors engineering (HFE) this situation has been studied, and evidence shows it contributes to two unwanted outcomes: poor situation awareness (SA) and high mental workload (MWL). SA is defined as a person's awareness and understanding of his or her situation. High MWL occurs when a person's mental capacity is exceeded. Both poor SA and high MWL ultimately impair memory, problem identification, decisionmaking, and decision execution and therefore have clear, negative impacts on safety. An intervention that provides better SA will reduce MWL and improve performance for the primary care physician (PCP) (problem identification, decisionmaking). The way to improve SA is to provide people with the right information at the right time. Thus our risk-informed intervention will test a SA intervention to improve PCP performance and thus safety of primary care of the elderly (aged 75+). The intervention involves a RN we call a "care coordinator" who (a) collects discrete patient data such as problem lists, medications, and tests and procedures from other providers 5 business days before a scheduled visit and (b) meets with the PCP at a scheduled time before the PCP's first visit to provide him/her with the right information at a time when the PCP can focus and talk. We use a randomized design involving four unrelated clinics, 16 primary care physicians, and 1,536 elderly patients randomly assigned to the intervention or care as usual. We will evaluate the impact on PCP SA and MWL, patient-perceived PCP SA, patient clinical outcomes, and return on investment. We will evaluate intervention barriers and facilitators and share the results widely with a theory-driven plan. This study is significant and innovative because we are (a) testing an intervention in primary care, which is understudied; (b) intervening for elderly patients, a priority population; (c) using a risk-informed safety intervention; (d) focusing on information chaos; and (e) involving a highly experienced multidisciplinary team of human factors engineers and primary care clinicians. [unreadable] [unreadable] PUBLIC HEALTH RELEVANCE: The study seeks to test an intervention for the safety of primary care of the elderly. The potential benefits are safer and more effective care, as well as more efficient care. This should result in better patient clinical process and outcomes measures and more efficient clinic operations. [unreadable] [unreadable] [unreadable]